There was a mistake and the pedal seemed to work properly due to the ultra-heavy amount of gain.I corrected a couple issues and now it works. Treat the SCOOP transistor (NPN MPSA06) like a PNP - that means collector to GND.Squarewave section TL072 has pin 3 and 5 connected to Vref.

Check the correct files below.

Also try different configurations on the pins of B100K (equalization) - depending on how you wire 1 and 3 it could act as a frequency cutter or the original EQ.Maybe try A100K for a better control.

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Seiche wrote:there's a difference between being drugged (I don't think it was only booze) and retarded.

i drew up my own PCB layout for it using the posted schematic and built & tested it, but i think that it has some errors. the tone control doesn't work like the sample videos and two of the positions on the rotary have VERY LOW output so, IMO, this one isn't quite solved yet.

Are you sure you did the very same of the schem? The only way you can have low output is by forgetting one of the input capacitors on the circuits (the 100 nf for example where the signal enters in the squarewave section of the circuitry) or on the same part of circuitry not connecting Vref to both pin 3 and 5 of the TL072. Don't look at the older post.

Seiche wrote:there's a difference between being drugged (I don't think it was only booze) and retarded.

Mine has the tone control like made in the layout (the 2nd one you're referring about). As I told in a previous post, one can try different pin wirings on the tone control depending on what is needed. In the last layout acts mostly like it's supposed to do, but you can wire it the opposite way to make it working like a low/high-pass filter.

The original one I reversed has a MPSA06 so it's weird the thing about using another one. Also I don't have some 05 at hand to test how and if it works, maybe check its pinout.But I don't think the low output is caused by this. Plus, I don't really have low output with my build, which is 100% like the last one you made reference to (the one with the better tone control and Vref on pins 3 and 5 of the TL072).

Seiche wrote:there's a difference between being drugged (I don't think it was only booze) and retarded.

i'm running an MPSA06 now and the scooped setting still has VERY low output. i did solve the square wave setting's low output by changing a couple resistor values from what is shown in this layout. i put the xformer on a seperate daughter board so i could try both types and make for easier placement/fitment in the enclosure.

well, i've checked everything and tried a zillion different transistors for the MPSA06 'scoop' circuit (i socketed that transistor) and it still has about a 10% or less of the volume than the other 4 settings. if i could just get it to be the same as the others, i'd probably be happy with it.

johnk wrote:well, i've checked everything and tried a zillion different transistors for the MPSA06 'scoop' circuit (i socketed that transistor) and it still has about a 10% or less of the volume than the other 4 settings. if i could just get it to be the same as the others, i'd probably be happy with it.

Weird wish I could mail or post a clip showing the volume I get, which is basically the same on every setting. Some extra punch on the Octave Clang section but it's ok.Did you tried reversing the MPSA06 using the opposite pinout?

Seiche wrote:there's a difference between being drugged (I don't think it was only booze) and retarded.

Hi John K,thanks for the circuit.I have a question about the leading space of the diodes in your layoutthat i notice it is 5 mm.Is there a reason for that and why not using a bit more like 8mmthat way you could install the diodes horizontally.Thanks,Mich P.

Mich P wrote:Hi John K,thanks for the circuit.I have a question about the leading space of the diodes in your layoutthat i notice it is 5 mm.Is there a reason for that and why not using a bit more like 8mmthat way you could install the diodes horizontally.Thanks,Mich P.

Hi Mitch, they fit just fine at 5mm so i just did it that way. i do that with 1N4148's too.

turdadactyl wrote:Maybe a dumb question, but why does this schematic use a 2x6 rotary and not a 2x5?

Hey there!My supplier sells 2x6 only.But on rotaries like these there is a metal ring with a tip. By adjusting the tip in the correct hole, you simply stops the rotations.So the standard has 6 positions, but you can reduce them to 3, 4, 5 depending on where you place the metal ring.Hope it's clear cheers!

Seiche wrote:there's a difference between being drugged (I don't think it was only booze) and retarded.

...I think is a propblem of the bias net...doesen't matter if the transistor is mps or bc, isn't a problem of beta, of course more is the beta and more is better, because is a emitter follower. Try to change the value of the 22k with 910k, probably you put the transintor in no saturation zone...sorry for my english, hope you can understand what I said...

i replaced the 22K base resistor with a 910K and the volume came up a lot (thanks!). it was still quite a bit lower output than the the other settings so i added a small clean booster after it and now they all pretty close to the same level when going thru the 5 rotary switch settings.